(2020-03-23)
Apparently the entire disk/cache directory has gone missing a while ago. We’re puzzled as to what caused this, still double-checking the archive to see if other files have disappeared. The files in disk/cache have been restored from a backup, apologies for the inconvenience. No files or meta-information (date of upload, number of downloads etc.) have been lost.
Update
(2020-04-09)
Found a few more missing files, all of them have been restored now - no data was lost. We implemented a bunch of sanity checks to hopefully prevent something like this from ever happening again.